What is the basic normal anatomy and sonographic imaging appearance of the thyroid gland? The thyroid gland is a butterfly-shaped organ located in the anterior neck, just below the thyroid cartilage and anterior to the trachea. It extends posteriorly to the esophagus and laterally to the carotid sheath, and consists of two lateral conically shaped …
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Why does the thermal index have a letter after it? The thermal index has three variants depending on the tissue types that will be encountered: TIs for soft tissue, TIb for bone, and TIc for the cranium. The thermal index is the ratio of the power being produced by the machine to the power needed …
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When should a yolk sac and an embryo be visible by Ultrasound? The yolk sac is usually seen at 5.5 weeks of gestation as a thin, circular structure, measuring between 3 and 5 mm. The embryo develops adjacent to the yolk sac and is usually seen around 6 weeks of gestation.
What is sinus tarsi syndrome? The sinus tarsi is a space in the hindfoot between the talus and calcaneus that normally contains fat and neurovascular structures. The sinus tarsi syndrome typically presents with lateral hindfoot pain and a subjective feeling of instability. The most common cause of sinus tarsi syndrome is prior ankle sprain, which …
What is the MRI appearance of stress fractures in the foot? Stress fractures occur as a result of chronic repetitive injury. The most common locations for stress fractures in the foot are the calcaneus and the metatarsal shafts. Fracture lines will appear as bandlike linear regions of low signal intensity on T1-weighted images. T2 weighted …
What is the tarsal tunnel, and what does it contain? The tarsal tunnel is located on the medial aspect of the ankle and contains the flexor tendons (posterior tibial, flexor digitorum longus, flexor hallucis longus) as well as the posterior tibial artery, vein, and nerve. The tunnel begins superiorly at the medial malleolus and extends …
What is plantar fibromatosis? Plantar fibromatosis is a benign fibrous proliferation of the plantar fascia, which occurs in all age groups and is bilateral in up to one third of cases. On MRI, there is nodular thickening of the plantar fascia that occurs in the medial or midportion of the fascia. T1-weighted and T2-weighted images …